Play behavior as an indicator of animal welfare: Disbudding in dairy calves

Abstract Play behavior may be reduced during negative experiences (e.g. pain) and serve as an indicator of animal welfare. To test this, the effects of a non-steroidal anti-inflammatory drug (NSAID) and a local anesthetic (LA) on dairy calf play behavior and wound sensitivity of calves after hot-iron disbudding (DB) were examined. Forty-six calves were assigned to six treatments: Sham, LA + Sham, LA + NSAID + Sham, DB, LA + DB and LA + NSAID + DB. Play behaviors, including bucking and running, as well as head-related behaviors were measured during a 10 min arena test 3 and 27 h after disbudding. Calves were tested in pairs (one experimental animal + companion), and all calves played at least once during the experiment. Three hours after disbudding, Sham, LA + NSAID + Sham and LA + NSAID + DB calves spent more time playing during the test period than calves in the DB treatment (Sham: 46 s/10 min, LA + NSAID + Sham: 46 s/10 min, LA + NSAID + DB: 33 s/10 min vs. DB: 11 s/10 min; SED: 10 s/10 min). Calves in the LA + Sham treatment spent less time playing than Sham calves 3 h after the procedure (LA + Sham: 18 s/10 min vs. Sham: 46 s/10 min; SED 10 s/10 min). Twenty-seven hours afterwards, effects of pain relief were seen, but were not consistent; some combinations of LA/NSAID/Sham treatments played more at this time, while others played less. There were no differences associated with disbudding 27 h after treatment, nor were there differences in head-related behaviors at either time. Wound sensitivity, as determined using von Frey monofilaments, was unaffected by pain relief. The areas medial to the wounds were less sensitive in disbudded animals from 3 to 75 h after the procedure, but locations lateral to the wound were more sensitive from 27 h and up to 75 h after the treatment. This is the first report that disbudding wounds may remain sensitive for at least 75 h after the procedure. These results also indicate that both disbudding and injection of LA can suppress play behavior in the short-term and that the need for longer-term pain management for hot-iron cautery disbudding of young calves requires further investigation.